Documentation would have you think that Migration.sol continues to be required

[bgravenorst]

Truffle has removed the requirement to use the Migration.sol contract. This file manages and updates the status of your deployed smart contract.

This contract is mentioned everywhere in the documentation (including the Pet Shop tutorial)

[gnidan]

We'll probably want to do this systematically, since this issue is likely not restricted to trufflesuite.com, but probably also extends to all of our boxes, various READMEs, and who knows what else!

Perhaps it would make sense first to identify all instances of problematic language, then figure out what exactly we want to say instead.